Top-50 cited articles on cysticercosis and neurocysticercosis

Background: Identifying the most highly cited papers in a given field can help researchers and professionals understand the milestones and research areas that are generating the most impact. This study aimed to identify and describe the 50 most frequently cited manuscripts on cysticercosis and neurocysticercosis. Methods: We identified the 50 most cited papers (articles and reviews) on cysticercosis and neurocysticercosis from the MEDLINE database and indexed in Web of Science-Core Collection, analyzing their bibliographic and content characteristics. Results: The most cited documents comprised 29 (58%) original articles and 21 (42%) reviews, the bulk of which were narrative reviews (n = 17), with a negligible presence of other types of reviews with high-level scientific evidence. Six journals published 42% of the articles. In addition to the USA, Mexico and Peru were prominent countries of origin among leading researchers. The main research topics were the central nervous system and epilepsy on the one hand, and diagnostic and therapeutic approaches on the other. Conclusion: Our findings shed light on the dissemination of knowledge about cysticercosis and neurocysticercosis in recent decades, identifying the most highly cited contributions that have driven research in the field.


Introduction
The growth in scientific knowledge on biomedicine has made it necessary to develop tools to manage and understand the body of evidence.Bibliometrics has become a well-established discipline for studying scientific activity and for describing the characteristics of different fields or areas of knowledge by quantifying the bibliographic characteristics of its literature. [1]At present, identifying citation classics and top-cited papers are the main bibliometric methods for systematically assessing research performance.Reviewing the most impactful papers can help guide future research and practice.4] Cysticercosis and neurocysticercosis are endemic to large swaths of territory in Asia, sub-Saharan Africa, and Latin America and are associated with deprivation and poor sanitation and hygiene. [5]Neurocysticercosis is responsible for 30% to 70% of epilepsies in some endemic countries and regions. [5]he diagnosis and antiparasitic treatment to reduce the rate of seizures due to neurocysticercosisis a relevant topic on research due to the public health problem. [5]This important public health challenge has thus attracted increasing research in the past several decades, but few studies have analyzed the scientific production on the diseases. [6,7]Reviewing the most impactful papers can help guide future research and practice so no studies have analyzed the top-cited documents in the literature.4] The review of the most important papers to help guide future research and practice in cysticercosis and neurocysticercosis.
This study identifies and reviews the top-cited articles on cysticercosis and neurocysticercosis.We describe and analyze their characteristics with an eye to determining the factors that have made them the most relevant papers for other researchers working in the field.This information can help researchers and professionals understand the milestones and the research areas that are generating the most impact.

Material and methods
Bibliographic searches were performed in the MEDLINE database, the main source of information in biomedicine.However, because we were undertaking a citation analysis, we used the Web of Science (WoS) platform to generate a ranking of the top-50 cited articles on cysticercosis and neurocysticercosis, as the WoS includes the MEDLINE database and also provides data on how frequently a particular article has been cited by others.
Two search strategies were combined to identify the included documents: we searched for the medical subject headings (MeSH) term "Cysticercosis" plus natural language appearing in the title and abstract fields.Using a thesaurus enables the precise identification of the literature related to the topic under study, while free-text terms ensure an exhaustive search that includes the most recent papers, which have not yet been assigned descriptors.
The search strategies used were as follows: In the MeSH thesaurus, the term "Neurocysticercosis" is a specific descriptor for cysticercosis, so all documents indexed with this descriptor were automatically retrieved in the wider search; moreover, both terms (along with their synonyms and variants) were included in the natural language searches.All the search results were combined with the OR operator, searched for in the WoS-Core Collection (WoS-CC) databases, and ranked by the number of citations received to identify the top-50 most cited research papers.All searches were performed in October 2022.
We excluded papers in which cysticercosis or neurocysticercosis was one of several diseases covered (e.g.epidemiological studies on neglected tropical diseases in general or several in particular), as well as generic documents mentioning cysticercosis or neurocysticercosis in other contexts, for example, with regard to diagnostic procedures or clinical studies on other diseases (See Supplementary table 1, http:// links.lww.com/MD/L698 for the list of excluded papers, with reasons).
We present the top-cited original articles (n = 29) separately from the top-cited reviews/ guidelines (n = 21) due to the different orientation and purpose of these document types.For each document, we recorded the following data: the full reference (authors' names, journal title, publication year), journal category in the WoS, countries of the first and last authors, and type of document (article, review, metaanalysis, trial).We assessed the full-text article to characterize the topic(s) covered and analyze their content.The citation density was calculated by dividing the number of citations by the journal position in its category in the Journal Citation Reports.
Ethical review, because this was an analysis of scientific production and had no human subjects, no ethics review was required.We performed an analysis on routine administrative data (MEDLINE and WoS); consent for publication is not applicable.

Results
The MEDLINE searches yielded 7860 documents, although only 5411 documents (68.8%) also included in WoS-CC were considered for the analysis.Nineteen documents among the most highly cited were excluded due to their lack of specific focus on cysticercosis or neurocysticercosis.
The 50 studies were published in 27 journals (Table 3), but 6 journals contained 44% of the included articles.Neurology was the most prolific, publishing 10% of top-cited papers, followed by the New England Journal of Medicine, Archives of Neurology, Clinical Infectious Diseases, Archives of Internal Medicine and the American Journal of Tropical Medicine and Hygiene.Regarding the dominant specialties, these comprised Neurology (30% of documents), General & Internal Medicine (28%) and Parasitology (22%).Other disciplines showed smaller contributions (Infectious Diseases, 14%; Microbiology, 6%; and Radiology, 2%) to the set of high-impact studies on cysticercosis and neurocysticercosis (Table 3).
The most frequent countries of origin among first authors were the USA and Peru (30% each), followed by Mexico (20%).Last authors were most often from the USA (34%), followed by Mexico and Peru (24% each), as shown in Table 4.The authors appearing most frequently in these leadership roles (first and last position) were García HH, Del-Brutto, OH and Sotelo J (Table 5).
Most (80%) of the top-50 cited documents were published from 1990 on (72% of articles and 90.5% of reviews) (Table 6).The most frequent topics in the included documents were the central nervous system & epilepsy and therapeutics (18% each, Table 7).Other prominent topics were epidemiology and diagnostics.

Discussion
11][12][13][14] An analysis of the top-cited articles illustrates how knowledge accumulates over time, so this study aimed to determine which articles on cysticercosis and neurocysticercosis have been most influential in the field.
In that regard, the evolution of scientific research on cysticercosis and neurocysticercosis has been driven by efforts to improve central nervous system problems (e.g.epilepsy, a complication of neurocysticercosis), treatment-related aspects (by means of 4 clinical trials), diagnostics, and epidemiological knowledge.The most cited article (638 citations) described an enzyme-linked immunoelectrotransfer blot-based assay for diagnosing human cysticercosis, published by Tsang et al [15] The most frequently cited review (537 citations) was led by Del-Brutto [16] and covered diagnostic criteria for neurocysticercosis.Other papers in the top 5 included a narrative review, led by García et al [17] about Taenia solium cysticercosis and its impact in neurological disease; a study by Sotelo et al [18] proposing diagnostic criteria for neurocysticercosis, which were the basis for the updated diagnosis criteria for neurocysticercosis proposed in Del-Brutto et al [16] review; and an original article by Osborn & Preece, [19] focusing on the differential diagnosis of cysticercosis and neurocysticercosis based on the study of many different intracranial cysts.
Other prominent contributions related to diagnostics included the paper by Schantz et al, [20] who studied 4 patients with recurrent seizures and brain lesions that were radiologically consistent with the presence of cysticercus; the authors concluded that recently arrived family members from countries where T solium was endemic were the most likely sources of infection.Additionally, Wilson et al [21] described the serological diagnosis of neurocysticercosis by enzyme-linked immunoelectrotransfer blot, while Yamasaki et al [22] described the molecular diagnosis of cysticercosis (DNA differential diagnosis of teniasis and cysticercosis by multiplex PCR).Del-Brutto et al [23] proposed diagnostic criteria for human cysticercosis and neurocysticercosis; Montano et al [24] analyzed the association between seizures, serology, and brain computed tomography (CT) abnormalities compatible with neurocysticercosis in Peru; and Rosas et al [25] studied enzyme-linked immunosorbent assay for diagnosing neurocysticercosis.
With regard to high-impact papers on treatment, García et al [26] reported a double-blind, placebo-controlled trial of albendazole plus dexamethasone versus placebo for neurocysticercosis; McCormick et al [27] analyzed 127 cases of cysticercosis cerebri or neurocysticercosis in USA; and Sotelo et al [28] described a series of 37 cases of neurocysticercosis treated with praziquantel.Six years later, the same group (Sotelo et al) [29] published a 4-arm randomized controlled trial of neurocysticercosis treatments (praziquantel 50 mg/kg/day for 15 days versus praziquantel 50 mg/kg/day for 8 days versus albendazole 15 mg/kg/day for 30 days versus albendazole 15 mg/kg/day for 8 days); at 3 months' follow-up, both praziquantel and albendazole were shown to be effective in eliminating cystic lesions on CT scans.In addition, Takayanagui & Jardim [30] published a clinical trial of albendazole and praziquantel; Escobedo et al [31] described treatment with albendazole; Del Brutto et al [32] performed a meta-analysis of cysticidal drugs for neurocysticercosis; and Sotelo et al [33] reported a controlled trial of albendazole versus praziquantel (20 patients in each group) for neurocysticercosis.
Among the papers that focused on epilepsy, Del-Brutto et al [34] described 203 patients with epilepsy secondary to neurocysticercosis; Medina et al [35] analyzed 100 Mexican patients with epilepsy that started after the age of 25 years-half the cases were due to neurocysticercosis; and García et al [36] analyzed the relationship between cysticercosis and epilepsy in Peru, finding that 12% of patients with epilepsy had positive serology for cysticercosis.
Other outstanding contributions among the 50 most cited papers include a proposal for vaccination against ovine cysticercosis in sheep [37] ; an article about a genetic characterization of the Asian Taenia [38] ; a Bayesian approach for estimating prevalence and diagnostic test characteristics of porcine cysticercosis [39] ; a proposal to declare neurocysticercosis an international reportable disease, published in the Bulletin of the World Health Organization [40] ; an analysis of the disease burden due to neurocysticercosis in a developing country [41] ; an analysis of prevalence and risk factors for T solium in Mexico [20] ; development of a monoclonal antibodies-based capture enzyme-linked immunosorbent assay of circulating parasite antigens of T solium [42] ; a research paper about the immune response in murine cysticercosis [43] ; and an epidemiological report of the emergence of T solium cysticercosis in Eastern and Southern Africa. [44]ost (80%) of the top-50 cited studies were published in 1990 or later (72% of articles and 90.5% of reviews), confirming the increase in research interest around the end of the century.This result is also associated with the phenomenon of obsolescence, and the likelihood that researchers will have a greater interest in more recent studies. [45]Of note, and in contrast to the typical situation in other areas of knowledge-characterized by the hegemony of authors from the USA or Europe among the most cited and seminal contributions [46] is the prominent position of authors from low-and middle-income countries.Another relevant finding is the high number of reviews among the top-cited documents (42%), well above the proportion of reviews relative to all the documents in the field (11.1%).This concentration of citations in reviews is a well-known phenomenon, but it highlights the relevance of this type of study for advancing knowledge. [47]That said, the performance of systematic reviews or other studies producing high-level scientific evidence should be encouraged to a greater extent, as their presence among the top-50 cited papers is negligible compared to the narrative reviews included in this set of documents. [48]his study has several limitations.First of all, citation analyses provide important information about a scientific paper impact, visibility, and use of the information contained therein, but they do not represent a measure of methodological quality or scientific evidence.Moreover, since the analysis focused on papers published in journals with an impact factor in WoS-CC, we may have missed relevant articles from non-Englishspeaking and endemic countries. [49,50]Other possible biases should also be considered, such as the tendency of some authors to omit citations of studies reporting well-known findings, or the association between the year of publication and the accumulation of citations, which may have led to overlooking important but recent papers that have not [50] yet garnered sufficient citations to be ranked within the top 50.Despite these limitations, citation analyses of top-cited documents are widely used to rank and evaluate a research field, and they provide information of great value to researchers and professionals in the area.

Conclusions
Our study provides information related to the dissemination of knowledge in recent decades about cysticercosis and neurocysticercosis, which may be helpful to researchers and professionals seeking to understand the research areas generating the most impact.Our results show the relevance of neurology and general and internal medicine in the area; the research leadership of Peru and Mexico, together with the USA; and the keen research interest in the central nervous system & epilepsy, diagnostics, and therapeutic approaches in relation to cysticercosis and neurocysticercosis.We also identify the most cited articles and reviews of reference in relation to all these aspects.

Table 1 (
Continued ) Ndimubanzi PC, Carabin H, Budke CM, et al A systematic review of the frequency of neurocyticercosis with a focus on people with epilepsy.PLoS

Table 3
Distribution of the top-50 cited papers on cysticercosis and neurocysticercosis by journal and category.

Table 4
Distribution of the top-50 cited papers on cysticercosis and neurocysticercosis, by country of origin of first and last authors.

Table 5
First and last authors with more than one of the top-50 cited papers on cysticercosis and neurocysticercosis, by number and type of publications.

Table 6
Top-50 cited papers on cysticercosis and neurocysticercosis, by decade of publication.

Table 7
Top-50 cited papers on cysticercosis and neurocysticercosis, by topic.